Thread (13 messages) 13 messages, 3 authors, 2018-11-15

[PATCH v3 6/7] arm64: docs: document KVM support of pointer authentication

From: Christoffer Dall <hidden>
Date: 2018-11-02 08:39:43
Also in: kvmarm, lkml

On Wed, Oct 17, 2018 at 04:17:59PM +0530, Amit Daniel Kachhap wrote:
quoted hunk ↗ jump to hunk
The documentation is updated to help in using pointer authentication
for KVM guests.

Signed-off-by: Amit Daniel Kachhap <redacted>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christoffer Dall <redacted>
Cc: Marc Zyngier <redacted>
Cc: kvmarm at lists.cs.columbia.edu
---
 Documentation/arm64/pointer-authentication.txt | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt
index 8a9cb57..b00d735 100644
--- a/Documentation/arm64/pointer-authentication.txt
+++ b/Documentation/arm64/pointer-authentication.txt
@@ -78,7 +78,13 @@ to TTBR1 addresses (e.g. kernel pointers).
 Virtualization
 --------------
 
-Pointer authentication is not currently supported in KVM guests. KVM
+Pointer authentication is enabled in KVM guest when virtual machine is
+created by passing a flag requesting this feature to be enabled. Without
+this flag, pointer authentication is not enabled in KVM guests and KVM
 will mask the feature bits from ID_AA64ISAR1_EL1, and attempted use of
 the feature will result in an UNDEFINED exception being injected into
 the guest.
+
+The flag to enable this feature is KVM_ARM_VCPU_PTRAUTH and should be
+used in KVM API KVM_ARM_VCPU_INIT. The pointer authentication key
+registers are hidden from userspace if this feature is not enabled.
-- 
2.7.4
I think this is placed in the wrong file.

Any information about the KVM API should go in
Documentation/virtual/kvm/api.txt.

The only information about KVM that belongs in this file would be host
running a VM with ptrauth can affect the host's ptrauth state (if that
applies).


Thanks,

    Christoffer
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